/*通配*/
*{
    margin: 0;
    padding: 0;
}
ul,li,a{
    list-style: none;
    text-decoration-line: none;
}

/*常用样式*/
.float-left{
    float: left;
}
.float-right{
    float: right;
}
.center{
    text-align: center;
}
.position-relative{
    position: relative;
}
.position-absolute{
    position: absolute;
}
.position-right{
    position: absolute;
    top: 0;
    right: 0;
}
.position-left{
    position: absolute;
    top: 0;
    left: 0;
}